1. Field of the Invention
The present invention generally relates to vehicle wheel covers with integral lug nut retention systems. More specifically, this invention relates to a theft deterrent full-face wheel cover that is snapped to the lug nuts of a wheel and is not removable without removing at least one lug nut.
2. Description of the Prior Art
Wheel covers have been used on vehicle wheels for many decades for purposes of aesthetic design, reduction in drag coefficient, and for improvement of brake cooling. Wheel covers have been fastened to wheels with a variety of devices including, clips, springs, and integral retaining features. In contrast, integral press-on wheel covers typically involve a cover body provided with integral tubular extensions or lug towers each having an integral projection for engaging a flange of a lug nut. With this particular style, the cover is integrally retained on the wheel by the cooperating interengagement of tubular extensions of the cover mounting to the lug nuts.
The tubular extensions are axially slotted to be divided into a plurality of cantilevered fingers, which cooperate with the lug nuts to retain the wheel cover thereto. The fingers of each tubular extension include integral radially extending abutments that resiliently engage within a radial recess of a respective lug nut to resiliently grip the lug nut and retain the cover thereto. Concurrent with receipt of the abutments in the radial recess, a tapered radial face on each finger engages an axially outwardly extending annular face of the lug nut in an attempt to provide a slight axial outward force on each finger to prevent axial shifting movement of the tubular extensions relative to the lug nuts.
The abutments describe a circle which is slightly less than the circle of the hexagonal portion of the lug nuts so that the fingers slightly separate or flex axially outwardly as the abutments move over the hexagonal portion of the lug nuts. Therefore, the fingers separate as the abutments move over a shoulder of the lug nuts until the abutments snap into the circumferential recess in each respective lug nut. When the abutments are received in the recess, the fingers return substantially to their normal molded shape.
One of several problems associated with this design is the adverse effects of tolerance stack ups between the axially outwardly extending annular face and the location of the recess on the lug nut. The fit of the cover to the lug nut depends on the depth and width of a recess that is on the lug nut and a tapered surface on the wheel face next to where the lug nut is seated. The tolerance build up among the radial tapered extension on the end of each finger of the cover, the lug nut, and the taper on the wheel's surface results in recess width variations that will prevent the radial tapered face of the abutment to move to the bottom of the recess, resulting in a loose fit on the lug nut, and a stress condition in the fingers of the retainer. Furthermore, such systems have several other drawbacks as described below.
For example, U.S. Pat. No. 4,707,035 to Kondo et al. teaches use of an integral press-on wheel cover for full-face wheel covering and not just half-face covering. Previously, only half size covers were used since there was no effective means for firmly locating the peripheral portion of the cover to the wheel. Accordingly, Kondo et al. disclose a wheel cover having a first fastening structure including cylindrical projections that are adapted to fit over and firmly grasp lug nuts of the wheel. The cylindrical projections are blind and do not include passages that extend through the face of the cover. Kondo et al. further discloses a second fastening structure including plate-like rim engaging projections that are adapted to snap into recesses in the rim for holding the periphery of the wheel cover against the wheel. Kondo et al. disclose that the second fastening structure is provided for preventing the rim engaging projections from being easily removed from the wheel. Regrettably, Kondo et al. thus has a very serious drawback.
Kondo et al. do not bother to disclose how the wheel cover is to be removed from the wheel. Since the cylindrical projections are blind and since there is no access to the lug nuts once the cover is fastened to the lug nuts, it would appear to be nearly impossible to remove the wheel cover without breaking it. One might attempt to pry the wheel cover off at the periphery with a tire iron, but would almost certainly fail to disengage both the periphery and the cylindrical projections without breaking the rim engaging projections or body of the wheel cover. Furthermore, there does not appear to be any way of removing the wheel cover at the lug nuts either, since access to the lug nuts is not provided with this design.
In another example, U.S. Pat. No. 5,163,739 to Stanlake, there is taught use of a full-face press-on wheel cover that requires a separate wire retainer. Stanlake discloses a wheel cover retention system having a wheel cover with open integral tubular extensions for attaching the wheel cover to lug nuts of a wheel. Each open tubular extension has flexible fingers for ratcheting over a flange on the lug nut and for gripping the flange. A wire retainer has rings encircling the fingers of each tubular extension for restricting removal of the wheel cover once assembled to the wheel. Unfortunately, this design requires use of a separate wire retainer to hold the cover to the wheel. Furthermore, there is no feature to limit overtravel of the cover as it is being applied to the wheel. Such overtravel can lead to fracture of the wheel cover, or rattling of the wheel cover due to inherent axial play.
Additionally, U.S. Pat. No. 5,595,422 to Ladouceur teaches a full-face press-on wheel cover having open integral tubular extensions. Ladouceur discloses a wheel cover having circumferentially spaced wells that grip lug nuts of a wheel and have integral cap portions for concealing the lug nuts of the wheel once the cover is assembled. Locking arms project axially from the wells to embrace the lug nuts to lock the cover securely to the wheel. Unfortunately, once the cover is assembled to the wheel, there is no way to remove the lug nuts since the integral cap portions block access thereto. Therefore, a separate anti-theft tool is required to release the locking arms from the lug nuts to remove the wheel cover.
Finally, U.S. Pat. No. 6,022,081 to Hauler et al. assigned to the assignee hereof teaches use of an ornamental wheel cover that is integrally retained on the lug nuts of a vehicle wheel and provides positive positioning of the cover to the lug nuts. The lug nuts preferably have a flange that defines an upper shoulder. The cover is provided with a number of elongated tubular extensions axially projecting from the cover that are each partially slotted to provide a plurality of cantilevered fingers. Each finger has a groove that has a shoulder, which positively positions the cover to the upper shoulder of the lug nuts of the wheel. Below the groove is a bulbous portion that contacts the lug nut below the flange. When the cover is attached to the wheel, the elongated tubular extensions are aligned with the lug nuts and the cover is moved axially inwardly of the wheel so that the cantilevered fingers separate slightly as the bulbous portions pass over the flange of the lug nut. The shoulder of the groove engages the upper shoulder of the lug nut flange, thereby providing a positive axial location of the cover to the wheel and eliminating the effects of misalignment of components due to tolerance stack ups. The bulbous portion passes over the flange of the lug nut and engages the underside of the flange, thereby retaining the cover on the lug nut. While the Hauler et al. patent No. 6,022,081 describes a simplified and novel approach to retain a wheel cover to a wheel, it does not address the problem of finding a simplified and novel way to retain a full-face wheel cover to a wheel so that the wheel cover is easily serviceable and removable.
Accordingly, what is needed is a full-face wheel cover having integral open tubular extensions that does not require use of a special tool to remove the wheel cover once assembled to the wheel, and also provides access to the lug nuts by an open well wrench for easy removal of the wheel cover. There is also a need for a wheel cover that provides positive axial positioning of the wheel cover relative to the wheel, thereby eliminating the effects of tolerance stack ups and the possibility of overtravel that result in poor fit of the cover to the wheel. There is also a need for a low-cost cover that attaches to the lug nuts with a fit that is independent of manufacturing tolerances outside of the physical dimensions of the nut itself, thereby eliminating the excessive variances that result from tolerance stack ups of several interrelated parts, i.e. the wheel cover, the lug nut, the wheel surface, and the interrelationship of all three items. Finally, there is a need for an integral one-piece wheel cover that does not require use of any separate retainers or fasteners.